تعریف موبایلیته حامل های شارژ
Mobailite-ye shārj-hā dar motavajeh be nisbat-e veloset-e gowd be sahneh-e barqiyi ke dar ravand-e havidar ast taein mishavad. Veloset-e gowd ba do mohasebat-e ensorat ast: tavane-ye sahneh-e barqi va mobailite-ye ravand. Baraye sahnihay-e barqi yeksān, metale fāghe mekhaneshoon baraye raveshe monaseb mobailite-ye shārj-hā darāyeh veldoset-e gowd-e mokhtalef hastand.
Dar metale, bande-ye elektronhā-ye valenz mitunad kamelān por nabashad va elektronhā-ye azādi dar movāred-e metal harekat konand. In elektronhā-ye azādi be atomhā-ye mokhtalefe peygir nadarand va dar khod-e metal be tarz-e mustaqil harekat mikonand.
Hala farz konim kih sahne-ye barqi-ye Ε volt/metre bar motefaveth-e metal lavashteh shode ast. Bazdeh be tasiri sahne-ye barqi, elektronhā-ye azādi mosbat mishavand. Lekin bazdeh be tabakhat bā ionhā-ye bish azan, veloset-e elektronhā mitunad be bi-nahāyat ziad nemishavad. Dar har tabakhat, elektron andāze-ye kārvāni-ye u rā mitunad verbed va pas az an baraye hazer budane sahne-ye barqi-ye khareji dobare teranj mishavad. Be in ravesh, elektronhā pas az zamān-e motefaveth-e sahne-ye barqi be veloset-e gowd-e pāyāni mirsabte midehand. Farz konim kih in veloset-e gowd v metre/sec ast. Bārid kari kari neveshte she kih miyonge-ye in veloset-e gowd-e elektronhā be tavane-ye sahne-ye barqi-ye Ε nesbat ast.
Anja, μ sabit-e nesbat ast ke ra mobailite-ye elektronha gofte mishavad. In mobailite neshon midehand kih che tor elektronha dar ravand harekat mikonand. Hambaste be veloset-e gowd-e pāyāni va harekat-e garmāyi-ye tasadofi-ye elektronha, jari-ye motefavethi bar ravesh-e vastane-ye sahne-ye barqi ast.
In parvane-ye jari-ye barqi ast. Jaryāni-ye jarāyebi-ye J barāye jari-ye barqiyi-ye hamvar ke dar ravand-e havidar per unit sekhm-e tarikhi-ye ravand lavashteh mishavad taein mishavad.
J = jaryāni-ye jarāyebi = jari-ye barqiyi per unit sath-e ravand. Be tavabe ehsasi tarif mishavad kih jaryāni-ye jarāyebi barāye jari-ye barqiyi-ye hamvar ke dar ravand-e havidar per unit sekhm-e tarikhi-ye ravand lavashteh mishavad.
Agar tadafoghol-e elektronhā per metrekub n boode,
nv = tedad-e elektronhā-ye ke per unit zamān per unit sekhm-e tarikhi-ye ravand lavashteh mishavad.
Pas, jame-ye kārvāni-ye ke per unit sekhm-e tarikhi-ye ravand per unit zamān lavashteh mishavad env کولوم است. In chizi nadarad jaryāni-ye jarāyebi-ye ravand ast.
Doubar barāye ravand-e havidar-e unit, sekhm-e tarikhi A = 1 m²
tol-e L = 1 m, sahne-ye barqi E = V/L = V/1 = V (V voltage-ye lavashteh bar ravand ast). Jari I = J va motāraje R = ρ = 1/σ, ke ρ resistivite-ye ravand va σ conductivite-ye ravand ast.
